input.match code example
Example: html5 input pattern name
echo '<input type="text" maxlength="32" name="first_name" pattern="[A-Za-z]{1,32}" value="'.$_SESSION['user_first_name'].'" required>';echo '<input type="text" maxlength="32" name="first_name" pattern="[A-Za-z]{1,32}" value="'.$_SESSION['user_first_name'].'" required>';